1. Field of the Invention
The present invention is directed to a method and apparatus for controlling data recording, a recording medium, and a computer program. In particular, the present invention is directed to a method and apparatus for controlling data recording, a recording medium, and a computer program for protecting data even when a recording process of the data has failed to normally complete on a random-access information recording medium.
2. Description of the Related Art
Magnetic tapes and optical disks are known as an information recording medium for recording video captured by a digital video camera. When data of a captured video and a collected audio (hereinafter a combination of video data and audio data is referred to AV (audio-visual) data) is recorded on the information recording medium, such as an optical disk that manages the AV data using a file system, video and audio are more quickly played from a desired location of the medium than on the magnetic tape.
The file system is recorded onto the optical disk subsequent to the completion of the recording of the AV data. The file system contains a file name of the AV data, and information about a recording position of the AV data on the optical disk.
The data recorded on the optical disk is managed according to the file system. For example, when the optical disk is played, a player acquires a file name of at least one file recorded on the optical disk, and a recording position of each file on the optical disk by referencing the file system recorded on the optical disk. When a user requests the player to play a desired file, the player identifies the recording position of the requested file, and reads the AV data from the recording position to play the AV data in accordance with the file system. The recording position is not necessarily collected at one location, and can be dispersed among a plurality of locations. In such a case, a plurality of dispersed locations corresponding to a single file are all recorded in the file system. Even when a file of data dispersed at a plurality of recording positions is played, all data dispersed is read.
If a power interruption takes place, for example, due to an erroneous battery removal, in the middle of the recording of the AV data onto an optical disk using a known recording apparatus, such as a digital video camera, the recording of the file system corresponding to the recorded AV data is terminated in an incomplete state thereof. If the playing of the optical disk is attempted when power is turned back on, the AV data is not recognized because of the absence of the corresponding file system. The playing of the AV data is thus difficult.
In order to recover the file system after the restoration of power even if the recording of the file system is incomplete due to the power interruption, information for restoring the file system is recorded onto the optical disk each time a single piece of AV data is recorded. When the power is turned back on, the file system is recovered based on the information. The AV data that was recorded until the power interruption can thus be played. Japanese Unexamined Patent Application Publication No. 10-177769 discloses such a technique.
In accordance with the disclosed technique, however, it takes substantial time to recover the file system based on the information after a power restoration. It is difficult to resume recording immediately subsequent to the power restoration without missing AV data recorded until the power interruption.
For example, should a battery be removed accidentally from a digital video camera for business use incorporating the above-referenced technique, a file system corresponding to AV data recorded heretofore could be unrecorded. When a battery is loaded again, a file system recovery process is performed to allow the AV data recorded until the recording interruption to be played. Since the recovery process of the file system takes substantial time, a photographer can miss an opportunity to photograph an important scene.
Such a recording interruption could take place in the recording of data other than the AV data.